Hydraulic tubing fitting seal

ABSTRACT

A seal for a flared end fitting, wherein the fitting includes a male portion having a tapered end, a female portion having a coordinated shape to the male portion, and a flow passage axially disposed in both female and male portions, the seal comprising: a frustoconical portion having an inner end and an outer end, wherein the inner end is circumferentially attached to one end of a cylindrical portion having two ends and coaxially disposed about the cylindrical portion, the cylindrical portion forms a flow passage through the seal, the frustoconical and cylindrical portions form a cavity that fits on the tapered end of the male portion of the fitting, and the cylindrical portion of the seal fits into the flow passage of the male portion of the fitting. A method of sealing a flared end fitting.

PRIORITY

The present non-provisional patent application claims benefit from U.S.Provisional Patent Application having Ser. No. 60/927,265, filed on May2, 2007, by Topping, and titled HYDRAULIC TUBING FITTING SEAL, whereinthe entirety of said provisional patent application is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention generally relates to hydraulic tubing fittings oradapters used to couple hydraulic tubing, and more particularly to aseal for hydraulic tubing fittings, which is used to eliminate leakageat coupling sites.

BACKGROUND OF THE INVENTION

Hoses, or tubing, are employed as flow conduit in fluid flow systems.Such tubing may be joined or coupled in such systems usingadapters/fittings. Such adapters or fittings are generally made of metal(e.g., stainless steel). One established type of adapter or fittingincludes a flare on an end of one tube that makes up a female portionabutted against a corresponding male portion connected to the end ofanother tube, which connects the tubes and effects a positive seal. Acompression nut and corresponding threads are usually used together toproduce an axial force on the male and female portions so that surfacesof the portions are placed under load in metal-to-metal contact witheach other to create the seal.

Various angles of flare have been employed in the United States andaround the world in such fittings. In particular, some commonly usedflared angles include precisely machined angles of 12, 30, 37 and 45degrees, for example.

One specific example of a flared fitting utilizing metal-to-metalcontact that is widely used is a fitting having a 37 degree flared orfrustoconical surface, which is known as a “Joint Industry Conference(JIC) fitting.” The JIC fitting was created by an organization offitting manufacturers in order to standardize the manufacture of 37degree flared angle fittings that were originally developed by theUnited States Air Force before World War II. The JIC also involved theSociety of Automotive Engineers (SAE) in the process of standardizingthe fitting, with the fitting becoming part of SAE J514 in 1950. The 37degree flared fitting later became an International Organization forStandardization (ISO) standard, ISO 8434, in 1986, which was replaced byISO 8434-2 in 1996.

FIG. 1 illustrates a side view of a JIC fitting for use in a fluidsystem, such as in an aircraft hydraulic or fuel system. The fitting 10includes a male portion 12 and a female portion 14. The exemplary JICfitting 10 is shown with the male 12 and female 14 portions separatedfrom one another, detached or uncoupled. The male portion 12 resembles acylindrical tube and includes a flow passage (not shown) that runsaxially throughout the portion 12 and that allows for transport offluids along its length and through its center. A seal is obtained bymating of a 37 degree frustoconical or beveled surface 16 on the outsideend 11 of the male portion 12 with a corresponding 37 degreefrustoconical or beveled surface 18 (not seen in Figure) inside thefemale portion or member 14. The female portion 14 also resembles acylindrical tube with a flow passage running axially throughout. Threads20 on the male member 12 mate threads in the female member (not shown)which function to draw the two beveled surfaces 16, 18 together when thetwo members are rotated with respect one another using hex heads 15, 32on the female and male portions 14, 12, respectively. The mated threadsfunction to hold the two portions 12, 14 together in order to helpeffect a seal at the two surfaces 16, 18. The fitting 10 holds and sealstwo sections of tubing together, with a first section 13 being attachedto the female portion 14 and a second section (not shown) being mated tothe male portion 12 using threads 17.

JIC fittings are used particularly in high pressure systems and aregenerally tight fittings that do not commonly experience leakage whenconnected for the first time. Heavy torque may be applied duringcoupling, however, which may deform the male portion when it is axiallyforced into the female fitting after the sealing surfaces already abuteach other. This possible damage to the fitting during assembly canprevent an effective seal from being formed in the fitting. Even if aneffective seal is formed in a fitting the first time it is used, damagemay be caused to the fitting during a disassembly, for example, thatcould prevent an effective seal from being produced in the fitting aftersubsequent reassembly. As a result, many fittings are not reused and areonly used once, which is costly. The seal in JIC fittings is formed withsmooth sealing surfaces. Blemishes may easily be introduced to thesmooth surfaces prior to, during or after assembly that may affect theseal. Also, foreign matter may contaminate the surfaces prior to, duringor after assembly. As a result of such deformation, blemishes andcontamination, a good seal may be prevented from being formed, which mayallow fluid leakage. Additionally, metal “creep” and cold flow over aduration of time may result in dimensional changes that permit leakagein such fittings.

One known modification to a hydraulic tubing fitting used to reduce orprevent fluid leakage is to machine an O-ring groove into a male portionand to include an O-ring in the groove. The purpose of the O-ring is tohelp seal the metal-to-metal surface between the male portion and afemale portion. A problem with such a modification, however, is that thegroove actually weakens the fitting. Additionally, O-rings work well forparallel surfaces, but do not perform as well to prevent leaks betweenbeveled surfaces as in JIC fittings.

Another known method used to prevent leaks in hydraulic tubing fittingsis to apply a layer of Teflon™ tape between female and male portions ofsuch a fitting. The tape is held in place between mated threads of thefemale and male portions. A problem with using Teflon™ tape, however, isthat the tape may become dislodged and contaminate the fluid runningthrough the tubing connected using the fitting. Another problem is thatTeflon™ tape is inconvenient to apply. Additionally, the tape may tearor otherwise be ineffective at sealing the connection.

Thus, a substantial need exists for an effective device and/or methodfor connecting and sealing JIC fittings or other flared end fittings,and that may allow the fittings to be reused with effective sealing. Itis desirable for such a device to be convenient to apply and economical,as well as effective.

SUMMARY OF THE INVENTION

The present invention teaches a device and a method used to seal ahydraulic tubing fitting or adapter to form a superior connectionbetween sections of tubing used in high pressure systems (e.g., ahydraulic fluid flow system). The purpose of such a device and/or methodis to effectively seal such a connection in order to prevent leakagefrom such a system and to prevent contamination of the system. Inparticular, a seal is used that cooperates with a fitting havingfrustoconical surfaces on male and female portions, such as a JICfitting, and fits between such portions in order to provide an effectiveseal. Such a seal is effective even if there is damage to the male andfemale portions of the fitting. In particular, the seal fits between thebeveled or frustoconical surfaces of the male and female portions of theJIC fitting, and is held in place by the two portions being connected toeach other (e.g., using mating threads on the two portions). It is,however, contemplated that the present invention may be used for anyflared end fittings, including, but not limited to, JIC fittings.

An advantage of using the device and method of the present invention isthat flared fittings connecting tubing in high pressure systems may beeffectively sealed even if such fittings include blemishes, deformationsand contaminating matter on sealing surfaces of the fittings. Aneffective seal can result from using the seal on a fitting that is beingreused. Additionally, the seals are economical and easy to use. Theseals are also easy to replace and are reusable. A further advantage isthat the seals are solid enough to be held in place on the fitting sothey will not become dislodged and contaminate a fluid flow system intowhich they are placed.

In one aspect, the present invention is a seal for a flared end fitting,wherein the fitting includes a male portion having a tapered end, afemale portion having a coordinated shape to the male portion, and aflow passage axially disposed in both female and male portions, the sealcomprising: a frustoconical portion having an inner end and an outerend, wherein the inner end is circumferentially attached to one end of acylindrical portion having two ends and coaxially disposed about thecylindrical portion, the cylindrical portion forms a flow passagethrough the seal, the frustoconical and cylindrical portions form acavity that fits on the tapered end of the male portion of the fitting,and the cylindrical portion of the seal fits into the flow passage ofthe male portion of the fitting. The fitting may be a JIC fitting. Theseal may comprise Teflon™. The fitting may include a seal surface oneach male and female portion where the portions substantially contacteach other when fit together, and the frustoconical portion of the sealis compressed between male and female portions of the fitting such thatthe frustoconical portion substantially contacts the seal surfaces ofboth male and female portions. The male and female portions of thefitting may substantially contact each other at an angle from a centralaxis of the fitting, and the frustoconical portion and cylindricalportion of the seal may be attached at an angle that is substantiallythe same as the angle of the seal surfaces of the fitting from thecentral axis. The female portion of the fitting may include aninternally threaded engaging portion, the male portion of the fittingmay include an externally threaded portion that mates in sealing contactwith the female portion, and the frustoconical portion of the seal maybe compressed by threadedly engaging the threaded engaging portions ofthe male and female portions.

Another aspect of the present invention is a method of sealing a flaredend fitting, comprising the steps of: providing a fitting that comprisesa male portion having a tapered end, a female portion having acoordinated shape to the male portion, and a flow passage axiallydisposed in both female and male portions, wherein the female and maleportions include means for engaging the two portions; providing a sealcomprising a frustoconical portion having an inner end and an outer end,wherein the inner end is circumferentially attached to one end of acylindrical portion having two ends and coaxially disposed about thecylindrical portion, the cylindrical portion forms a flow passagethrough the seal, the frustoconical and cylindrical portions form acavity that fits on the tapered end of the male portion of the fitting,and the cylindrical portion of the seal fits into the flow passage ofthe male portion of the fitting; placing the seal on the tapered end ofthe male portion of the fitting with the cylindrical portion of the sealextending into the flow passage of the male portion of the fitting;engaging the male and female portions of the fitting together; andcompressing the seal between the male and female portions of thefitting.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other advantages of the present invention, andthe manner of attaining them, will become apparent and the inventionitself will be better understood by reference to the followingdescription of the embodiments of the invention taken in conjunctionwith the accompanying drawings, wherein like structure is referred to bylike numerals throughout the figures, and wherein:

FIG. 1 is a side view illustration of disassembled male and femaleportions of a JIC fitting;

FIG. 2 is a side view of the disassembled JIC fitting of FIG. 1 andshown including a seal in accordance with the present invention;

FIG. 3 is a sectional view of a tubing fitting, including female andmale portions of the connection, and also including a sectional view ofa seal, in accordance with the present invention, shown retained betweenthe male and female portions;

FIG. 4 is a schematic illustration of a seal in accordance with thepresent invention;

FIG. 5 is a side view illustration of a seal in accordance with thepresent invention; and

FIG. 6 is a bottom view illustration of a seal in accordance with thepresent invention.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS

Although the present application focuses on devices and/or methods forsealing JIC fittings, the present application contemplates using thepresent invention to effectively seal any type of flared end fitting oradapter. In particular, the focus will be on sealing flared end fittingsin hydraulic fluid systems. However, it is contemplated that the presentinvention may be used in any type of system in which flared end fittingsare used.

With reference to the accompanying figures, wherein like components arelabeled with like numerals throughout the figures, an illustrative sealfor JIC fittings and other flared end fittings is disclosed, taught andsuggested by the multiple embodiments.

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather the embodimentsare chosen and described so that others skilled in the art mayappreciate and understand the principles and practices of the presentinvention.

The principles of the present invention may be practiced in any instancein which it is desired to effectively seal a flared end tubing fittingor adapter that connects sections of tubing in a high pressure system(e.g., hydraulic fluid system). In particular, the present invention maybe used to seal such fittings that may have been disconnected andreconnected subsequent to an initial connection, and that may haveincurred damage. Again, for purposes of explanation, the invention willgenerally be described with regard to a seal for a JIC fitting. However,the present invention may be used with other flared end fittings. Someexamples of other possible fittings include, but are not limited to, SAE45 degree flare couplings, Parker Triple Thread (PTT) 30-degree flarecouplings and Japanese Industrial Standardization (JIS) 30 degree flareparallel thread couplings.

For purposes of illustration, the present invention will be describedwith respect to a representative fitting 10 shown disassembled in FIGS.1 and 2, with FIG. 2 including a seal 50, in accordance with the presentinvention. FIG. 2 shows how the seal 50 can fit and can be retainedbetween male 12 female 14 portions of the fitting 10. The purpose of theseal 50, shown in FIG. 2, is to effectively seal the JIC fitting 10between the male and female portions 12, 14. The seal 50 fits over abeveled or frustoconical surface 16 on a tapered end 11 of an extension34 of the male portion 12. The female portion 14 is connected to themale portion by fitting over and surrounding the male extension 34 andthe seal 50. Threads 20 on the male extension 34 preferably mate withcorresponding threads in the inside of female portion 14 (not shown) tosecure the two portions 12, 14 together with the seal 50 retainedbetween the portions 12, 14. A hex head 15 or the like may be providedon female member 14 to allow tightening with a wrench. As shown, femaleportion 14 is connected, opposite the seal 50 and male portion 14, to asection of tubing 13. Means for attachment of the male member 12 toanother section of tubing (not shown), such as by using threads 17 thatmate with threads on the section of tubing, for example, may also beprovided. A hex head 32 or the like may be provided on the male portion12 for tightening purposes. Other similar arrangements are alsocontemplated that would allow the portions 12, 14 of the fitting 10 tobe attached to sections of tubing opposite where the portions 12, 14 arejoined or connected using the seal 50.

FIG. 3 is a partial sectional view of an assembled tubing fitting 10(e.g., JIC) including seal 50. The fitting 10 comprises a female portion14 including a threaded port 22 and a male portion 12 including threads20. Female portion 14 of the fitting 10 includes a port body 26 with thethreaded port 22 extending inwardly from an end face 28 to form theinternally threaded port 22. The port body 26 also has provided thereina flow passage 30, which is smaller in diameter than that of threadedport 22, and a frustoconical or beveled seal surface 18 located betweenthreaded port 22 and flow passage 30. Preferably, female portion 14 is astandard female member that is part of a JIC fitting. Male portion 12 ofthe fitting 10 is adapted to mate in sealing contact with the threadedport 22 of the female portion 14 along frustoconical surface 16. Maleportion 12 is also preferably a standard male member that is part of aJIC fitting. Male portion 12 preferably includes a hexagonal nut portion32 (i.e., hex head) and an externally threaded male extension 34 thatcan threadedly engage the internally threaded port 22. Male portion 12also has an internal flow passage 36 that is coaxial with and cancommunicate with the flow passage 30 of the female portion 14 while inan assembled condition of connection. The flow passages 30, 36 maypreferably be cylindrical in shape, although other shapes are alsocontemplated. Male portion 12 also has a standard frustoconical orbeveled seal surface 16 constructed and arranged to be positioned insealing contact with seal surface 18 of female portion 14 by thethreaded engagement between threaded portions 20 and 22. A mating angle,at which the male seal surface 16 and female seal surface 18 may mate(without seal 50 present), is 37 degrees for a JIC fitting. This angleis taken with respect to the central axis (indicated by 17 in Figures)of the fitting. Other mating angles may, however, be employed in thepresent invention. Additionally, components used to connect the male andfemale portions 12, 14 of the fitting other than the nuts and threadsdescribed and shown are also contemplated by the present invention. Anysuch components may be used in the present invention in order to bringthe surfaces 16 and 18 into sealing contact with seal 50 and retain suchsealing contact.

FIG. 3 also includes a sectional view of an embodiment of the seal 50 ofthe present invention. The seal 50 shown has a frustoconical portion 52that, as shown, contacts the female portion beveled surface 18 at afirst surface 54 and contacts the male portion beveled surface 16 at asecond surface 56. The seal 50 also includes a cylindrical portion 58that is attached to the frustoconical portion 52 of the seal 50 towardsthe interior of the frustoconical portion 52 or seal 50. With regard tothe fitting 10, the cylindrical portion 58 attaches to the frustoconicalportion 52 of the seal 50 distal to the male extension 34 of the fitting10 and extends and preferably rests against sides of the flow passage 36of the male portion 12 and further extends generally parallel to an axisrunning through the flow passage 36. A purpose of the cylindricalportion 58 is to help to hold the seal 50 in place between the male andfemale 12, 14 portions, so that an effective seal can be formed betweenthe male and female portions 12, 14. The diameter of the cylindricalportion 58 is preferably slightly less than the diameter of the flowpassage 36 of the male portion 12. Cylindrical portion 58 may berelatively smooth such that it is able to slide and snugly fit into flowpassage 36 of the male portion 12. However, alternatively, cylindricalportion 58 may be threaded to mate and engage with possible threadslocated on the walls of the flow passage 36.

Cylindrical portion 58 is preferably shaped to fit in the flow passage36 of the male portion 12. Since the flow passage 36 may havealternative shapes to the cylindrical one shown in FIG. 3, thecylindrical portion 58 may similarly be alternatively shaped.

FIG. 4 is a schematic illustration of an embodiment of the seal 50 ofthe present invention. The seal 50 as shown is configured to fit over amale extension or portion of a flared end fitting 10 such that thetapered end (11 in FIGS. 1 and 2) of the male portion 12 can fit insidethe cavity 64. The seal 50 is also configured so that a female portion14 of the fitting 10 can fit over the seal 50 when it is assembledtogether with the male portion 12. The seal 50 includes a frustoconicalportion 52 that can contact a seal surface of the female portion 14 ofthe flared end fitting 10 at a first surface 54 and can contact a sealsurface of the male portion 12 at a second surface 56. The frustoconicalportion 52 has two ends, which include an inner end 55 and an outer end59, with the terms “inner” and “outer” relating to how the ends relateto a central flow axis 19 through the seal 50, with the central flowaxis 19 being inside the seal 50. The frustoconical portion 52 iscircumferentially attached to one end 63 of a cylindrical portion 58that has two ends 61, 63, with the frustoconical portion 52 beingcoaxially disposed about the cylindrical portion 58. The frustoconicalportion 52 is also connected to the cylindrical portion 58 at an angle,with the angle 57 generally matching the angle that the male and femaleportions of the fitting meet together at the sealing surfaces, such as37 degrees for a JIC fitting. Such an angle is taken with respect to thecentral flow axis 19, as discussed above.

The cylindrical portion 58 preferably fits within a flow passage (36 inFIG. 3) of the male portion 12 of the fitting. The cylindrical portion58 has a first surface 60 that contacts the wall of the flow passage ofthe male portion and a second surface 62 that defines a flow passagethrough the seal 50. Preferably, the cylindrical portion 58 fits in theflow passage of the male portion in order to help hold the seal 50 inplace for a more effective seal of the fitting.

The cylindrical portion 58 may have a shape other than the cylindricalone shown. The shape of such a flow passage portion of the seal 50 mayhave a shape to match the shape of the flow passage of the male portionof the fitting.

FIG. 5 shows a side view illustration of an embodiment of the seal 50 ofthe present invention. The dashed lines show a cross sectional view ofthe frustoconical and cylindrical portions 52, 58 and how they meet at adesired angle 57 to generally match that of a flared end fitting. Thecavity 64 that is defined by the frustoconical 52 and cylindrical 58portions is formed in order to accommodate an end of a male portion of aflared end fitting.

FIG. 6 shows a view of the seal 50 of FIG. 5 from the bottom 66 of theseal 50.

The seal 50 may be machined or molded (e.g., injection molding), or madeusing any other similar process. The seal 50 is preferably preciselymachined such that the angle of the frustoconical portion 52 withrespect to the cylindrical (or other shaped) portion 58 preciselyconforms with mated male and female portion surfaces 16, 18 and the flowpassage 36 of the male portion 12. The seal 50 is secured in place in afitting by mating male and female portions 12, 14 and the seal 50preferably remains stable until fitting 10 is disassembled.

Preferably, the seal 50 is formed from one piece of material. However,it is also possible that the seal may be made by attaching separatelyformed pieces together.

The seal 50 may be made from any material suitable for providing asealed connection. Preferably, the seal 50 comprises a material ofsufficient rigidity such that the seal 50 may fit in the fitting withoutbeing dislodged from between male and female portions of the fittingwhile fluid, for example, flows through the fitting. Additionally,preferably, the seal 50 comprises a material that is compatible with, orinert to, all anticipated chemicals and materials that could come intocontact with the seal 50 during use. The seal 50 may comprise a singlematerial, a blend of materials, composite material, and the like.Preferably, the material has a certain Durometer Hardness so as to allowthe seal 50 to be retained in its desired position between male 12 andfemale 14 portions of a fitting 10. One particularly preferred materialfor the seal 50 is Teflon™. Another possible material is a deformablebut noncompressible elastomeric material, such as a natural or syntheticrubber. The material used for the seal 50 is not, however, limited tothe materials listed and may comprise any suitable material for forminga seal between male and female portions 12, 14 of any flared fittingwhere it is considered useful to seal the fitting with a seal of thepresent invention.

Preferably, for a JIC fitting, the seal 50 has an outside diameter ofabout 37 to 39 mm and an inside diameter of about 24 mm. The seal 50preferably snugly fits a male portion 12 having a flow passage 36diameter of about 27 mm. Also, preferably, the seal 50 has a height of 6mm. These dimensions are preferred, however, and apply for a seal matingto a JIC fitting. Different dimensions of the seal 50 are, however,contemplated for other fittings.

Referring to FIGS. 2 and 3, in order to use the seal 50, the fitting 10is disassembled, and the seal 50 is placed on the end 11 of theextension 34 of the male portion 12 of the fitting 10 with thecylindrical portion 58 fitting inside the flow passage 36 of the maleportion 12. The cylindrical portion 58 extends into a portion of theflow passage 36 in the male portion 12 of the fitting 10 in order toallow the seal 50 to be securely held in place in the flow passage 36when the male 12 and female 14 portions of the fitting 10 are compressedtogether. Preferably, the cylindrical portion 58 fits snugly in the flowpassage 36 of the male portion 12 of the fitting 10. If the cylindricalportion 58 of the seal 50 includes threads, then the seal 50 is screwedonto the male portion 12 such that threads on the seal 50 mate withthreads in the flow passage 36 of the male portion 12. The frustoconicalportion 52 of the seal 50 is placed over the male portion 12 such thatportion 52 contacts sealing surface 16 at a surface 52. The femaleportion 14 is then placed over the seal 50 and extension 34 of the maleportion 12. The male 12 and female 14 portions are then threadedly, orotherwise, engaged, with the seal 50 being retained between the twoportions 12, 14. The sealing surface 18 of the female portion 14 thencontacts the surface 54 of the seal 50. The frustoconical portion 52 ofthe seal 50 is compressed between sealing surfaces 16 and 18 to producean effective sealing relationship. The seal 50 preferably conformsitself to any irregularities in the surfaces 16, 18, such as scratches,dents, etc., and will produce an effective seal.

Hydro-testing and flow performance testing was performed on seals of thepresent invention that mated with JIC fittings. A JIC fitting wasassembled with a seal of the present invention being placed between maleand females portions of the fitting. Water was moved through the fittingusing hydraulic pressures of up to about 200 psi. The fitting and sealcombination was checked for visible leaks. No leaks were observed.

Other embodiments of this invention will be apparent to those skilled inthe art upon consideration of this specification or from practice of theinvention disclosed herein. Various omissions, modifications, andchanges to the principles and embodiments described herein may be madeby one skilled in the art without departing from the true scope andspirit of the invention which is indicated by included claims.

1. A seal for a flared end fitting, wherein the fitting includes a maleportion having a tapered end, a female portion having a coordinatedshape to the male portion, and a flow passage axially disposed in bothfemale and male portions, the seal comprising: a frustoconical portionhaving an inner end and an outer end, wherein the inner end iscircumferentially attached to one end of a cylindrical portion havingtwo ends and coaxially disposed about the cylindrical portion, thecylindrical portion forms a flow passage through the seal, thefrustoconical and cylindrical portions form a cavity that fits on thetapered end of the male portion of the fitting, and the cylindricalportion of the seal fits into the flow passage of the male portion ofthe fitting.
 2. The seal of claim 1, wherein the fitting is a JICfitting.
 3. The seal of claim 1, wherein the seal comprises Teflon™. 4.The seal of claim 1, wherein the fitting includes a seal surface on eachmale and female portion where the portions substantially contact eachother when fit together, and the frustoconical portion of the seal iscompressed between male and female portions of the fitting such that thefrustoconical portion substantially contacts the seal surfaces of bothmale and female portions.
 5. The seal of claim 4, wherein the male andfemale portions of the fitting substantially contact each other at anangle from a central axis of the fitting, and the frustoconical portionand cylindrical portion of the seal are attached at an angle that issubstantially the same as the angle of the seal surfaces of the fittingfrom the central axis.
 6. The seal of claim 4, wherein the femaleportion of the fitting includes an internally threaded engaging portion,the male portion of the fitting includes an externally threaded portionthat mates in sealing contact with the female portion, and thefrustoconical portion of the seal is compressed by threadedly engagingthe threaded engaging portions of the male and female portions.
 7. Amethod of sealing a flared end fitting, comprising the steps of:providing a fitting that comprises a male portion having a tapered end,a female portion having a coordinated shape to the male portion, and aflow passage axially disposed in both female and male portions, whereinthe female and male portions include means for engaging the twoportions; providing a seal comprising a frustoconical portion having aninner end and an outer end, wherein the inner end is circumferentiallyattached to one end of a cylindrical portion having two ends andcoaxially disposed about the cylindrical portion, the cylindricalportion forms a flow passage through the seal, the frustoconical andcylindrical portions form a cavity that fits on the tapered end of themale portion of the fitting, and the cylindrical portion of the sealfits into the flow passage of the male portion of the fitting; placingthe seal on the tapered end of the male portion of the fitting with thecylindrical portion of the seal extending into the flow passage of themale portion of the fitting; engaging the male and female portions ofthe fitting together; and compressing the seal between the male andfemale portions of the fitting.
 8. The method of claim 7, wherein thefitting is a JIC fitting.
 9. The method of claim 7, wherein the sealcomprises Teflon™.
 10. The method of claim 7, wherein the fittingincludes a seal surface on each male and female portion where theportions substantially contact each other when fit together, and thefrustoconical portion of the seal is compressed between male and femaleportions of the fitting such that the frustoconical portionsubstantially contacts the seal surfaces of both male and femaleportions.
 11. The method of claim 10, wherein the male and femaleportions of the fitting substantially contact each other at an anglefrom a central axis of the fitting, and the frustoconical portion andcylindrical portion of the seal are attached at an angle that issubstantially the same as the angle of the seal surfaces of the fittingfrom the central axis.
 12. The method of claim 7, wherein the femaleportion of the fitting includes an internally threaded engaging portion,the male portion of the fitting includes a externally threaded portionthat mates in sealing contact with the female portion, and thefrustoconical portion of the seal is compressed by threadedly engagingthe threaded engaging portions of the male and female portions.